1. Field
Embodiments relate to a power storage apparatus.
2. Description of the Related Art
Recently, the European Union has decided upon a plan to expand the percentage of renewable energy, from among all electric power sources, up to 20% by the year 2020 and 50% by the year 2050. The U.S.A. is also planning to carry out Renewable Portfolio Standards (RPS). In a situation where renewable energy increases from less than 5% today to up to 30 to 40% in the future, of all the electric power sources, power systems must be prepared for a new change.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of skill in the art.